1. Fermilab Nov. 30, 2005 Włodek Guryn Results from the PP2PP Experiment at RHIC and Future Plans Włodek Guryn Brookhaven National Laboratory, Upton, NY, USA OUTLINE of the TALK Description of the experiment Description of analysis Results and interpretation Future plans with STAR

2. Fermilab Nov. 30, 2005 Włodek Guryn The Relativistic Heavy Ion Collider RHIC is a QCD Laboratory: Nucleus- Nucleus collisions (AuAu, CuCu…); Asym. Nucl. (dAu); Polarized proton-proton; eRHIC - Future

3. Fermilab Nov. 30, 2005 Włodek Guryn RHIC p  p  accelerator complex BRAHMS & PP2PP STAR PHENIX AGS LINAC BOOSTER Pol. Proton Source Spin Rotators 20% Snake Siberian Snakes 200 MeV polarimeter AGS quasi-elastic polarimeter Rf Dipoles RHIC pC “CNI” polarimeters PHOBOS RHIC absolute pH polarimeter Siberian Snakes AGS pC “CNI” polarimeter 5% Snake

4. Fermilab Nov. 30, 2005 Włodek Guryn Total and Differential Cross Sections, and Polarization Effects in pp Elastic Scattering at RHIC S. Bültmann, I. H. Chiang, R.E. Chrien, A. Drees, R. Gill, W. Guryn*, J. Landgraf, T.A. Ljubičič, D. Lynn, C. Pearson, P. Pile, A. Rusek, M. Sakitt, S. Tepikian, K. Yip Brookhaven National Laboratory, USA J. Chwastowski, B. Pawlik Institute of Nuclear Physics, Cracow, Poland M. Haguenauer Ecole Polytechnique/IN2P3-CNRS, Palaiseau, France A. A. Bogdanov, S.B. Nurushev, M.F Runtzo, M. N. Strikhanov Moscow Engineering Physics Institute (MEPHI), Moscow, Russia I. G. Alekseev, V. P. Kanavets, L. I. Koroleva, B. V. Morozov, D. N. Svirida ITEP, Moscow, Russia S. Khodinov, M. Rijssenbeek, L. Whitehead, S. Yeung SUNY Stony Brook, USA K. De, N. Guler, J. Li, N. Ozturk University of Texas at Arlington, USA A. Sandacz Institute for Nuclear Studies, Warsaw, Poland * spokesman

5. Fermilab Nov. 30, 2005 Włodek Guryn p pp p + p pp p Pomeron (C=+1) Odderon (C=  1) + Perturbative QCD Picture s = (p 1 + p 2 ) 2 = (C.M energy) 2 t = (p 1 – p 3 ) 2 = - (four momentum transfer) 2 s    t  1 (GeV/c) 2 – Non-perturbative regime Elastic scattering d  /dt + optical theorem  total cross section  tot P, O Vacuum QM exchanged ? p1p1 p2p2 p3p3 p4p4 Process of Elastic Scattering

6. Fermilab Nov. 30, 2005 Włodek Guryn M Summary of the Existing Data (unpolarized) 50500 PP2PP Highest energy so far: pp: 63 GeV (ISR) pp: 1.8 TeV (Tevatron) pp2pp energy range: 50 GeV   s  500 GeV pp2pp |t|-range: (at  s = 500 GeV) 410 –4 GeV 2  |t |  1.3 GeV 2 One cannot assume that because of the existence of the models, the data in pp at the ISR, and pp data at SppS and the Tevatron one can predict with sufficient accuracy d  /dt and  tot in the RHIC  s range.

7. Fermilab Nov. 30, 2005 Włodek Guryn PP2PP Forward slope B from 2002 engineering run dd dt =  G E     t2t2    tot 2 e +Bt   G E   tot e +½Bt t + + [ ] C Fit |t |-distribution with Using fits to world data of  tot  51.6 mb and  0.13 Fit B for 0.010 GeV 2  |t |  0.019 GeV 2 B = ( 16.3  1.6  1.0) GeV -2 Depends on detector position Depends on beam transport element positions B = ( 16.3  1.6  1. ) GeV -2 Phys. Lett. B 579 (2004) 245-250

8. Fermilab Nov. 30, 2005 Włodek Guryn Cross sections for polarized beams Cross-section, azimutual angular dependence for transversely polarized beams, with polarizations P B and P y :

9. Fermilab Nov. 30, 2005 Włodek Guryn Five helicity amplitudes describe proton-proton elastic scattering Some of the measured quantities are: Helicity Amplitudes in Elastic Scattering

10. Fermilab Nov. 30, 2005 Włodek Guryn Source of single spin analyzing power A N Single spin asymmetry A N arises in the CNI region is due to the interference of hadronic non-flip amplitude with electromagnetic spin- flip amplitude. Any difference from the above is an indication if other contributions, hadronic spin flip caused by resonance (Reggeon) or vacuum exchange (Pomeron) contributions. B. Z. Kopeliovich and L. I. Lapidus Sov. J. Nucl. Phys. 114 (19) 1974 N. H. Buttimore, B. Z. Kopeliovich, E. Leader, J. Soffer, T. L. Trueman, Phys. Rev. D59, (1999) 114010. A N (t)

11. Published A N Measurements in the CNI Region pp Analyzing Power no hadronic spin-flip -t A N (%) E704@FNAL p = 200 GeV/c PRD48(93)3026 E950@BNL p = 21.7 GeV/c PRL89(02)052302 with hadonic spin-flip no hadronic spin-flip pC Analyzing Power r 5 pC  F s had / Im F 0 had Re r 5 = 0.088  0.058 Im r 5 =  0.161  0.226 highly anti-correlated

12. Fermilab Nov. 30, 2005 Włodek Guryn Experimental Determination of A N Use Square-Root-Formula to calculate spin ( ,  ) and false asymmetries ( ,  ). Since the above is a relative measurement the efficiencies  (t,  ) cancel Asymmetry “False” Asymmetry

13. Fermilab Nov. 30, 2005 Włodek Guryn Principle of the Measurement Elastically scattered protons have very small scattering angle θ *, hence beam transport magnets determine trajectory scattered protons The optimal position for the detectors is where scattered protons are well separated from beam protons Need Roman Pot to measure scattered protons close to the beam without breaking accelerator vacuum Beam transport equations relate measured position at the detector to scattering angle. x 0,y 0 : Position at Interaction Point Θ* x Θ* y : Scattering Angle at IP x D, y D : Position at Detector Θ x D, Θ y D : Angle at Detector =

14. Fermilab Nov. 30, 2005 Włodek Guryn The Setup

15. Fermilab Nov. 30, 2005 Włodek Guryn The PP2PP Experimental Setup to IR Roman Pot below the beam Roman Pot above the beam

16. Fermilab Nov. 30, 2005 Włodek Guryn Si Detector Package 4 planes of 400 µm Silicon microstrip detectors: –4.5 x 7.5 cm 2 sensitive area –good resolution, low occupancy –Redundancy: 2X- and 2Y-detectors –Closest proximity to the beam ~14 mm –8 mm trigger scintillator with two PMT readout behind Silicon planes Run 2003: Silicon manufactured by Hamamatsu Al strips: 512 (Y), 768 (X), 70µm wide 100 µm pitch implanted resistors guard ring 1 st strip  edge: 490 µm bias ring Si Detector board LV regulation SVXIIE Signal/noise  20

17. Fermilab Nov. 30, 2005 Włodek Guryn Trigger Active area Acceptance beam pipe shadow Only “inner” pots used for trigger and analysis, biggest acceptance Analyze the data for the closest position (¾ of all data)

18. Fermilab Nov. 30, 2005 Włodek Guryn Elastic Event Identification An elastic event has two collinear protons, one on each side of IP 1.It also has eight Si detector “hits”, four on each side. 2.Clean trigger: no hits in the other arm and in inelastic counters. 3.The vertex in (z 0 ) can be reconstructed using ToF.

19. Fermilab Nov. 30, 2005 Włodek Guryn Hit Correlations Before the Cuts Events with only eight hits Width is mainly due to beam emittance ε = 15 π mm · mrad spread of vertex position σ z = 60 cm Note: the background appears enhanced because of the “saturation” of the main band It is due mainly to beam halo and beam-gas interactions After the cuts the background in the final sample is ≈ 0.5% ÷ 2% depending on y (vertical) coordinate

20. Fermilab Nov. 30, 2005 Włodek Guryn Elastic Event Selection 1.Match of coordinates on opposite sides of IP; within 3 σ for x and y coordinates. 2.Hit coordinates to be in the acceptance area of the detector. 3.Events with multiple matches were excluded. After the cuts 1.14 million elastic events in t-interval [0.010, 0.030] (GeV/c) 2 Loss of elastic events due to the selections < 0.035

21. Fermilab Nov. 30, 2005 Włodek Guryn Collinearity:  x before and after z-correction, and  y  x ) = 130  rad  x ) = 100  rad  y ) = 70  rad

22. Fermilab Nov. 30, 2005 Włodek Guryn Determination of A N Use Square-Root-Formula to calculate raw asymmetries. 1.It cancels cancel luminosity dependence and effects of apparatus asymmetries. 2.It uses ,  bunch combinations. Since A N is a relative measurement the efficiencies  (t,  ) cancel Asymmetry

23. Fermilab Nov. 30, 2005 Włodek Guryn Results: Full bin 0.01 < -t < 0.03 (GeV/c) 2 Fit  N cos(  ) dependence to obtain A N Note: The calculated false asymmetry  F = -0.0011 is consistent with measured  F = -0.0016 P Y (+-,-+)=0.476  0.085 P B (+-,-+) =0.430  0.089 P B + P Y = 0.877  0.149 Arm A Arm B Statistical errors NN P Y (++,--)=0.345  0.066 P B (++,--) =0.532  0.106

24. Fermilab Nov. 30, 2005 Włodek Guryn Systematic Errors on A N luminosities ans detector efficiencies cancel---- background4.5% beam positions at the detectors1.8% corrections to the standard transport matrices1.4% uncertainties on L x eff and L y eff 6.4% neglected term with double-spin asymmetries2.8% All above8.4% Beam polarization error17.0%

25. Fermilab Nov. 30, 2005 Włodek Guryn where t c = -8π α / σ tot and κ is anomalous magnetic moment of the proton The fit to measured A N (t) gives Re r 5, Im r 5 Determination of r5 for p  p  →pp in the CNI Region

26. Fermilab Nov. 30, 2005 Włodek Guryn Results: A N and r 5 Statistical and systematic errors added in quadratures 17.0% normalisation error due to beam polarisation uncertainty, not included Re r 5 = -0.042 ± 0.037, Im r 5 = -0.51 ± 0.60

27. Fermilab Nov. 30, 2005 Włodek Guryn stat + sys errors used in fits preliminary with hadronic spin-flip hadronic spin – flip contribution consistent with zero (1  level) Im r 5 = 0.002  0.029 Re r 5 = -0.006  0.007  2 /ndf = 10 / 12 uncertainty on the  (  =  0.03) parameter can change at the same level A N : RHIC Polarized Jet Target  s =14 Gev A. Bravar, Dubna, Sept. 29, 2005

28. Fermilab Nov. 30, 2005 Włodek Guryn Reminder: Cross sections for polarized beams Cross-section, azimutual angular dependence for transversely polarized beams, with polarizations P B and P y :

29. Fermilab Nov. 30, 2005 Włodek Guryn Calculation of double spin asymmetries Luminosity normalization is done using: 1.The machine bunch intensities:L ij ~  I i B ·I j Y over bunches with given i,j combination 2.The inelastic counters The two methods agreed. Distributions  (  ) were fitted with (P 1 ·sin 2  + P 2 ·cos 2  ) where P 1 =P B ·P Y ·A SS and P 2 =P B ·P Y ·A NN Raw asymmetry: Statistical errors only PRELIMINARY

30. Fermilab Nov. 30, 2005 Włodek Guryn Results: A NN and A SS |t|-range, (GeV/c) 2, (GeV/c) 2 A SS  Ass (stat.) A NN  Ann (stat.)  2 /n 0.010-0.0300.019-0.00670.00560.02480.015425.3/20 E.Leader, T.L. Trueman PRD 61 077504 (2000)  2 /  + =0.05(1+i)           i T.L. Trueman Odderon Searches at RHIC Workshop Sept. 2005

31. Fermilab Nov. 30, 2005 Włodek Guryn Future Program: PP2PP and STAR Physics Processes I In t-channel it is an exchange with quantum numbers of vacuum pp pp Non Pert. QCD pp pp PQCD picture pp pp

32. Fermilab Nov. 30, 2005 Włodek Guryn Physics Processes II Gluon Ladders Gluonic Exchanges These processes are mediated by gloun rich exchanges

33. Fermilab Nov. 30, 2005 Włodek Guryn Elastic and Inelastic Processes In terms of QCD, Pomeron exchange consists of the exchange of a color singlet combination of gluons. Hence, triggering on forward protons at high (RHIC) energies predominantly selects exchanges mediated by gluonic matter. For each proton vertex one has t four-momentum transfer  p/p M X invariant mass

34. Fermilab Nov. 30, 2005 Włodek Guryn Central Production in DPE In the double Pomeron exchange process each proton “ emits ” a Pomeron and the two Pomerons interact producing a massive system M X. The massive system could form resonances or consist of jet pairs. Because of the constraints provided by the double Pomeron interaction, glueballs, and other states coupling preferentially to gluons, will be produced with much reduced backgrounds compared to standard hadronic production processes.

35. Fermilab Nov. 30, 2005 Włodek Guryn Time Projection Chamber: 45 padrow, 2 meters (radius),  dE/dx)  8%, -1<  Multi-gap Resistive Plate Chamber TOFr: 1 tray (~1/200),  (t)=85ps STAR Detector

36. Fermilab Nov. 30, 2005 Włodek Guryn STAR Detector Forward   Detector (FPD) Pb-glass EM calorimeter Shower-Maximum Detector (SMD) Preshower STAR TPC: -1.0 <  < 1.0 FTPC: 2.8 <  < 3.8 FPD: |  |  3.8 (p+p) |  |  4.0 (p+p, d+Au)

37. Fermilab Nov. 30, 2005 Włodek Guryn TPC dE/dx at low p T M. Anderson et al., Nucl. Instrum. Meth. A 499, 659 (2003)

38. Fermilab Nov. 30, 2005 Włodek Guryn Resonance Signal in p+p and Au+Au collisions from STAR K(892)   (1520) p+p Au+Au  (1385) p+p Au+Au    (1020) p+p Au+Au p+p

39. Fermilab Nov. 30, 2005 Włodek Guryn Leading particle spectra` Charged hadron p T distributions measured up to 12 GeV in Au+Au, d+Au and p+p reference

40. Fermilab Nov. 30, 2005 Włodek Guryn Implementation at RHIC Need detectors to tag forward protons and detector with good acceptance and particle ID to measure central system Roman Pots of pp2pp and STAR

41. Fermilab Nov. 30, 2005 Włodek Guryn Physics with Tagged Forward Protons with the STAR Detector at RHIC H. Spinka Argonne National Laboratory, USA R.E. Chrien, R. Gill, W. Guryn*, B. Hackenburg, J. Landgraf, T.A. Ljubičič, D. Lynn, C. Pearson, P. Pile, S. Tepikian, K. Yip Brookhaven National Laboratory, USA A. A. Bogdanov, S.B. Nurushev, M.F Runtzo Moscow Engineering Physics Institute (MEPHI), Moscow, Russia I. G. Alekseev, V. P. Kanavets, L. I. Koroleva, B. V. Morozov, D. N. Svirida ITEP, Moscow, Russia B. Surrow MIT, Boston USA S. Khodinov, M. Rijssenbeek SUNY Stony Brook, USA A.Sandacz Soltan Institue for Nuclear Studies, Warsaw, Poland *Contact person E-mail guryn@bnl.govguryn@bnl.gov Phone (631) 344 3878

42. Fermilab Nov. 30, 2005 Włodek Guryn Acceptance Studies SDD and DPE Single proton in the Roman Pot Two protons are detected

43. Fermilab Nov. 30, 2005 Włodek Guryn Summary 1.We have measured the single spin analyzing power A N in polarized pp elastic scattering at  s = 200 GeV, highest to date, in t-range [0.01,0.03] (GeV/c) 2. 2.The A N is  4-5  from zero. 3.The A N is   away from a CNI curve, which does not have hadronic spin flip amplitude. 4.In order to understand better underlying dynamics one needs to map  s and t- dependence of A N and also measure other spin related variables (A NN, A SS, A LL, A SL ). 5.Preliminary result on A NN, A SS has been obtained. 6.The program of elastic scattering measurements will continue by joining STAR experiment.

44. Fermilab Nov. 30, 2005 Włodek Guryn Summary The physics program of tagged forward protons with STAR at RHIC can: 1.Study standard hadron diffraction both elastic and inelastic and its spin dependence in unexplored t and  s range; 2.Study the structure of color singlet exchange in the non-perturbative regime of QCD. 3.Search for central production of light and massive systems in double Pomeron exchange process - glueballs. 4.Search for an Odderon - an eigenstate of CGC. 5.At RHIC II one would take advantage of smaller TPC, include more coverage to better characterize rapidity gaps. Those studies will add to our understanding of QCD in the non-perturbative regime where calculations are not easy and one has to be guided by measurements. There is a great potential for important discoveries

45. Fermilab Nov. 30, 2005 Włodek Guryn Future Possibility – Big Improvement  s (GeV) ** |t|-range (Gev/c) 2 Typical errors 20020 m0.003 < |t| < 0.02  B = 0.3,  tot = 2 – 3 mb  = 0.007 and  A N =0.002 x-y Full acceptance at  s 200 GeV Without IPM and kicker With IPM and kicker dN/dt

46. the left – right scattering asymmetry A N arises from the interference of the spin non-flip amplitude with the spin flip amplitude (Schwinger) in absence of hadronic spin – flip contributions A N is exactly calculable (Kopeliovich & Lapidus) hadronic spin- flip modifies the QED ‘predictions’ hadronic spin-flip usually parametrized as A N & Coulomb Nuclear Interference  1) p  pp had needed phenomenological input: σ tot, ρ, δ (diff. of Coulomb-hadronic phases), also for nuclear targets em. and had. formfactors

47. Fermilab Nov. 30, 2005 Włodek Guryn p  p  Collider at RHIC

48. Fermilab Nov. 30, 2005 Włodek Guryn Hit selection in Si detectors

49. Fermilab Nov. 30, 2005 Włodek Guryn Acceptance Study DPE Two protons are detected

50. Fermilab Nov. 30, 2005 Włodek Guryn Reconstruction of the Momentum Loss   Accelerator transport 1.Need to measure vector at the detection point, hence two RPs are needed on each side of STAR. 2.For a proton, which scatters with  and  we have:

51. Fermilab Nov. 30, 2005 Włodek Guryn A NN and A SS The spin dependent elastic cross section is:  =  0 [1+A N (P b +P y )n+A NN (P b n)(P y n)+A SS (P b s)(P y s)] where n-unit vector of normal to scattering plane, k=p/|p| is p-beam momentum s=n  k Note: s is not radial In the case of both beams polarized vertically:  =  0 [1+A N (P b +P y )cos  +P b P y (A NN cos 2  +A SS sin 2  )] Due to vertical orientation of RP (  =  /2) pp2pp in run 2003 was more sensitive to A SS than to A NN.

52. Fermilab Nov. 30, 2005 Włodek Guryn A NN, A SS raw asymmetries Distributions  (  ) were fitted with (P 1 ·sin 2  + P 2 ·cos 2  ) P 1 =P B ·P Y ·A SS and P 2 =P B ·P Y ·A NN Statistical errors only PRELIMINARY